Formatted question description: https://leetcode.ca/all/1476.html

1476. Subrectangle Queries (Medium)

Implement the class SubrectangleQueries which receives a rows x cols rectangle as a matrix of integers in the constructor and supports two methods:

1. updateSubrectangle(int row1, int col1, int row2, int col2, int newValue)

  • Updates all values with newValue in the subrectangle whose upper left coordinate is (row1,col1) and bottom right coordinate is (row2,col2).

2. getValue(int row, int col)

  • Returns the current value of the coordinate (row,col) from the rectangle.

 

Example 1:

Input
["SubrectangleQueries","getValue","updateSubrectangle","getValue","getValue","updateSubrectangle","getValue","getValue"]
[[[[1,2,1],[4,3,4],[3,2,1],[1,1,1]]],[0,2],[0,0,3,2,5],[0,2],[3,1],[3,0,3,2,10],[3,1],[0,2]]
Output
[null,1,null,5,5,null,10,5]
Explanation
SubrectangleQueries subrectangleQueries = new SubrectangleQueries([[1,2,1],[4,3,4],[3,2,1],[1,1,1]]);  
// The initial rectangle (4x3) looks like:
// 1 2 1
// 4 3 4
// 3 2 1
// 1 1 1
subrectangleQueries.getValue(0, 2); // return 1
subrectangleQueries.updateSubrectangle(0, 0, 3, 2, 5);
// After this update the rectangle looks like:
// 5 5 5
// 5 5 5
// 5 5 5
// 5 5 5 
subrectangleQueries.getValue(0, 2); // return 5
subrectangleQueries.getValue(3, 1); // return 5
subrectangleQueries.updateSubrectangle(3, 0, 3, 2, 10);
// After this update the rectangle looks like:
// 5   5   5
// 5   5   5
// 5   5   5
// 10  10  10 
subrectangleQueries.getValue(3, 1); // return 10
subrectangleQueries.getValue(0, 2); // return 5

Example 2:

Input
["SubrectangleQueries","getValue","updateSubrectangle","getValue","getValue","updateSubrectangle","getValue"]
[[[[1,1,1],[2,2,2],[3,3,3]]],[0,0],[0,0,2,2,100],[0,0],[2,2],[1,1,2,2,20],[2,2]]
Output
[null,1,null,100,100,null,20]
Explanation
SubrectangleQueries subrectangleQueries = new SubrectangleQueries([[1,1,1],[2,2,2],[3,3,3]]);
subrectangleQueries.getValue(0, 0); // return 1
subrectangleQueries.updateSubrectangle(0, 0, 2, 2, 100);
subrectangleQueries.getValue(0, 0); // return 100
subrectangleQueries.getValue(2, 2); // return 100
subrectangleQueries.updateSubrectangle(1, 1, 2, 2, 20);
subrectangleQueries.getValue(2, 2); // return 20

 

Constraints:

  • There will be at most 500 operations considering both methods: updateSubrectangle and getValue.
  • 1 <= rows, cols <= 100
  • rows == rectangle.length
  • cols == rectangle[i].length
  • 0 <= row1 <= row2 < rows
  • 0 <= col1 <= col2 < cols
  • 1 <= newValue, rectangle[i][j] <= 10^9
  • 0 <= row < rows
  • 0 <= col < cols

Related Topics:
Array

Solution 1. Brute force

// OJ: https://leetcode.com/problems/subrectangle-queries/

// Time:
//      O(MN) for SubrectangleQueries and updateSubrectangle
//      O(1) for getValue
// Space: O(MN)
class SubrectangleQueries {
    vector<vector<int>> A;
public:
    SubrectangleQueries(vector<vector<int>>& rectangle) : A(rectangle) {}
    void updateSubrectangle(int row1, int col1, int row2, int col2, int newValue) {
        for (int i = row1; i <= row2; ++i) {
            for (int j = col1; j <= col2; ++j) {
                A[i][j] = newValue;
            }
        }
    }
    int getValue(int row, int col) {
        return A[row][col];
    }
};

Solution 2.

// OJ: https://leetcode.com/problems/subrectangle-queries/

// Time:
//      O(MN) for SubrectangleQueries
//      O(1) for updateSubrectangle
//      O(Update) for getValue
// Space: O(MN)
class SubrectangleQueries {
    vector<vector<int>> A, sub;
public:
    SubrectangleQueries(vector<vector<int>>& rectangle) : A(rectangle) {}
    
    void updateSubrectangle(int row1, int col1, int row2, int col2, int newValue) {
        sub.push_back({ row1, col1, row2, col2, newValue });
    }
    
    int getValue(int row, int col) {
        for (int i = sub.size() - 1; i >= 0; --i) {
            if (row >= sub[i][0] && row <= sub[i][2] && col >= sub[i][1] && col <= sub[i][3]) return sub[i][4];
        }
        return A[row][col];
    }
};

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